SIST EN 15938:2010

SLOVENSKI STANDARD
oSIST prEN 15938:2009
01-julij-2009
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Automotive fuels - Ethanol blending component and ethanol (E85) fuel - Determination of
electrical conductivity
Kraftstoffe für Kraftfahrzeuge - Ethanol Mischungskomponent und Ethanolkraftstoff (E85)
- Bestimmung der elektrischen Leitfähigkeit
Carburants pour automobiles - Ethanol comme base de mélange à l'essence et
carburant éthanol (E85) - Détermination de la conductivité électrique
Ta slovenski standard je istoveten z: prEN 15938
ICS:
75.160.20 7HNRþDJRULYD Liquid fuels
oSIST prEN 15938:2009 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 15938:2009

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oSIST prEN 15938:2009
EUROPEAN STANDARD
DRAFT
prEN 15938
NORME EUROPÉENNE
EUROPÄISCHE NORM
April 2009
ICS 75.160.20

English Version
Automotive fuels - Ethanol blending component and ethanol
(E85) fuel - Determination of electrical conductivity
Carburants pour automobiles - Ethanol comme base de Kraftstoffe für Kraftfahrzeuge - Ethanol
mélange à l'essence et carburant éthanol (E85) - Mischungskomponent und Ethanolkraftstoff (E85) -
Détermination de la conductivité électrique Bestimmung der elektrischen Leitfähigkeit
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee CEN/TC 19.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations which
stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other language
made by translation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the
same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are aware and to
provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without notice and
shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2009 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 15938:2009: E
worldwide for CEN national Members.

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oSIST prEN 15938:2009
prEN 15938:2009 (E)
Contents Page
Foreword .3
1 Scope .4
2 Normative references .4
3 Terms and definitions .4
4 Principle .5
5 Reagents .6
6 Apparatus .6
7 Sampling .6
8 Procedure .7
9 Expression of results .8
10 Precision .8
11 Test report .9
Bibliography . 10

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oSIST prEN 15938:2009
prEN 15938:2009 (E)
Foreword
This document prEN 15938:2009 has been prepared by Technical Committee CEN/TC 19 “Gaseous and
liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the secretariat of
which is held by NEN.
This document is currently submitted to the CEN Enquiry.
This document was prepared by CEN/TC 19’s Ethanol Task Force under responsibility of its Working
Group 21 and is based on DIN 51627-4 [1].
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oSIST prEN 15938:2009
prEN 15938:2009 (E)
1 Scope
This document specifies a test method for the determination of the electrical conductivity in ethanol and
ethanol fuel in the range from approximately (0,3 to 5) µS/cm at a temperature of 25 °C. The electrical
conductivity is determined from the measured electrical conductance.
The electrical conductivity is an important analytical criterion for the ascertainment and control of anionic and
cationic components in ethanol and ethanol fuel. Some of these components can exhibit corrosive properties.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
EN ISO 3170, Petroleum liquids — Manual sampling (ISO 3170:2004)
EN ISO 3171, Petroleum liquids — Automatic pipeline sampling (ISO 3171:1988)
3 Terms and definitions
For the purposes of this document, the following terms and definitions.
3.1
electrical conductance
G
reciprocal value of the electrical resistance
–1
NOTE The electrical conductance is expressed in siemens (S) or Ω .
3.2
electrical resistance
R
measurement value of a sample, directly determined by means of the conductivity meter, which increases with
the sample length l and decreases with the sample cross-section A
NOTE The electrical resistance of a sample is expressed in ohms (Ω). The relation between R and the electrical
conductance (3.1) is shown in equation (1).
1
G = (1)
R
3.3
electrical conductivity
σ
T
material-dependent measure of the electrical current conducted in an electrical field by the ions present in the
solution
NOTE 1 The material-dependent electrical conductivity of a solution is related to the electrical current which is
achieved by moving ions of the solution in an electrical field. It is therefore applicable as a method to limit ionic
contamination in alcohols and alcohol based fuels. The electrical conductivity σ is determined in accordance with
T
equation (2) from the determined electrical conductance G (3.1) and the geometrical dimensions of the measuring cell
(length and effective cross-section) which are added to form the cell constant K (3.4).
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oSIST prEN 15938:2009
prEN 15938:2009 (E)
l
σ =G⋅ =G⋅K (2)
T
A
where
-1 -1 -1
4
σ is the electrical conductivity of the sample, in µS cm (1 S m = 10 µS cm ), at the measurement temperature T,
T
in °C;
l is the length of the measured section (geometrical electrode gap), in m or, following the respective unit conversion, in
cm, with 1 m = 100 cm;
2 2
A is the effective cross-section of the measuring cell, in m or, following the respective unit conversion, in cm , with
4
2 2
1 m = 10 cm ;
–1 –1
K is the cell constant of the measuring cell in m or, following the respective unit conversion, in cm , with
–1 –1
1 m = 0,01 cm .
NOTE 2 The electrical conductivity of a solution depends on the temperature; therefore the temperature is given
together with the measurement value. Hence the electrical conductivity, which is mostly determined at 25 °C, is
designated as σ .
25
NOTE 3 The electrical conductivity depends on ion concentration, ion type, temperature and viscosity of the solution.
Therefore its measurement range can be large. "Ultrapure" (deionized and demineralised) water for example, due to its
-1 -1
self-dissociation at 25 °C, has an electrical conductivity of 0,054 83 µS cm (5,483 µS m ).
3.4
cell constant
K
the geometrical dimensions of the measuring cell which are added to form one value
NOTE The electrical conductivity σ (3.3) cannot be calculated simply from the electrical resistance R (3.2) and the
geometrical cell dimensions because its functional relationship to the cell dimensions is very complex, especially in cases
where the geometry is not cubical. Therefore, the measuring cell is calibrated by means of a calibration solution of known
*
electrical conductivity σ . The cell constant K is determined in accordance with equation (3) from the determined electrical
*
conductance G* caused by the calibration solution and its known electrical conductivity σ .
*
σ
25
K = (3)
*
G
25
where
–1 –1
K is the cell constant of the measuring cell in m or, following the respective unit conversion, in cm
-1 –1
(1 m = 0,01 cm );
*
G is the electrical conductance at 25 °C in the measuring cell filled with the calibration solution, expressed in S;
25
* -1 -1 -1 -1
4
σ is the electrical conductivity of the calibration solution at 25 °C, in S m or µS cm (1 S m = 10 µS cm ).
25
4 Principle
The determination of the electrical conductivity in ethanol or ethanol fuel is
...